I have the same problem as ykmd and the replies so far haven't helped, unfortunately. I'd make a new thread but this one is not that old, so I think it appropriate to post in here.
I have the makecurrent() at the beginning of paintGL() and the swapbuffers() call at the very end. However, I only get a flickering screen. That is, the screen in my GLWidget is all black and only goes to my set background color (a kind of light gray) while redrawing, for example if i resize the window.
Does anyone know why that could be?